The heredity of acquired characters in plants / by the Rev. Professor George Henslow.

  • Henslow, George, 1835-1925.
Date:
1908
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Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The heredity of acquired characters in plants / by the Rev. Professor George Henslow. Source: Wellcome Collection.

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    2 INTRODUCTION [chap. to definite or indefinite results. By the term ' definite action ' I mean an action of such a nature that when many individuals of the same variety are exposed during several generations to any change in their physical conditions of life, all, or nearly all, the individuals are modified in the same manner. A new sub- variety would then be produced without the aid of selection.^ The reader will note the cause of both indefinite and definite variations is attri¬ buted to changed conditions of life. Sir E. R. Lankester distinguished the former as birth- variations spontaneously (arising) by innate variability. ... Nothing done to them after birth . . . causes the desired characteristic [in breeding]. It appears unexpectedly, almost unaccountably as an inborn quality. ^ He is here alluding to what Darwin called individual differences.^ From such, natural selection is supposed to select the fittest to survive. The characteristics of a race or species are maintained by natural selection, just as much as they are produced by it. In these words Sir E. R. Lankester is evidently not in accordance with Darwin, who attributes in¬ definite variations to the external conditions of 1 Au. and PL under Dom.^ p. 271. 2 Science from an Easy Chair/' Daily Telegraph, 22nd February 1906. ^ Origin, etc., 6th ed., p. 34.